Avionics cargo hold module having an upper integrated floor

ABSTRACT

An integral avionics bay module. The module has a structure that has an integral cabin floor on top that closes the structure. Installing such an integral avionics bay structure in a single operation inside a primary fuselage structure considerably reduces the integration time on the final assembly line for the aircraft.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of the French patent application No.1262592 filed on Dec. 21, 2012, the entire disclosures of which areincorporated herein by way of reference.

BACKGROUND OF THE INVENTION

The invention relates to an avionics bay module, to an aircraft noseincorporating such a module, and to a method of integrating such a nose.

FIG. 1 shows a nose of a prior art aircraft 10, which nose includes aprimary fuselage structure 12.

The primary structure 12 comprises in particular a plurality of fuselageframes 14 arranged parallel to one another along the longitudinal axis Xof the nose. Only the top portions of the fuselage frames 14 are shownfor reasons of clarity.

The structure 12 also has a well 18 for storing the nose landing gear(not shown) of the aircraft.

The primary fuselage structure 12 defines a space inside the structurethat is to be fitted out.

More particularly, a cabin floor 20 extends longitudinally from the rearend 10 a of the nose to a radome zone 22 situated at the front end 10 bof the nose.

The floor 20 subdivides the inside space for fitting out into an upperspace and a lower space.

A zone dedicated to the cockpit 24 is for fitting out in the upper spaceabove the wheel well 18.

A zone dedicated to an avionics bay 26 is for fitting out in the lowerspace. This zone comprises a zone referred to as a “front” zone 26 aincluding the wheel well 18 (under the cockpit zone 24) and a zonereferred to as a “rear” zone 26 b situated behind the wheel well, underthe floor 20 of the upper space 28, which is dedicated to a passengercabin.

Fitting out the rear zone 26 b can take a relatively long time. Theavionics racks and the avionics systems incorporating electrical and/orelectronic equipment are put into place one by one in the zone inquestion and subsequently they are interconnected (electricity, air, . .. ) and they are also connected to electrical systems and air pipesystems installed in the primary structure 12.

The various above-mentioned tasks require a relatively long period ofintegration time on the assembly line for the nose. It would beadvantageous to be able to shorten this integration time.

SUMMARY OF THE INVENTION

To this end, the present invention provides an avionics bay module,characterized in that it comprises an avionics bay structure oflongitudinal axis for installing in a single operation in a primaryfuselage structure of an aircraft, the avionics bay structure having anintegral floor in its top portion.

The floor already integral with the top of the structure of the moduleserves to reduce the overall integration time of the aircraft when thestructure of the module (prepared away from the final assembly line ofthe aircraft) is installed in a primary fuselage structure.

The integral floor of the structure also makes it possible for themodule to be more compact and to increase the usable space inside themodule for installing racks and equipment therein.

The floor thus forms an integral portion of the avionics bay structure(module) even before it is installed in the primary fuselage structure.The floor carried by the avionics bay structure can thus be connected tothe floor that is already present in the primary fuselage structure. Thefloor of the avionics bay structure is connected to the location wherethe floor is voluntarily and locally interrupted in the primarystructure for the purpose of receiving the avionics bay structuretogether with its floor.

Prior to being installed in the primary fuselage structure, the avionicsbay structure comprises in particular an assembly of racks enabling itto receive various pieces of electrical and/or electronic equipmenttogether with most of that equipment (some predetermined amount definedin advance when designing the module) already installed in the rackstogether with interconnections between these pieces of equipment, andalso ventilation system elements (air ducts, couplings, . . . ).

Thus, the module may be installed in a single operation in the primarystructure where previously the avionics bay racks for receiving thevarious pieces of equipment dedicated to the avionics bay used to beinstalled rack by rack on the final assembly line and where the piecesof equipment and the interconnections between them were then put intoplace after the racks had been installed. Once the module is installedit is thus almost ready for use, apart in particular from adding thelast pieces of equipment (e.g., avionics computers, . . . ) and the lastconnections (electricity, air) inside the module and also withcorresponding systems associated with the primary fuselage structure.

The saving in time obtained during this operation also makes it possibleto reduce the overall integration time on the final assembly line of theaircraft.

According to one possible characteristic, the avionics bay structurecomprises a plurality of elements fastened to one another so as to forman assembly that is suitable for being moved as a unit.

The structure of the bay module is thus made up of an assembly ofelements (racks, pieces of electrical and/or electronic equipment,interconnection elements between those pieces of equipment, ventilationsystem elements, . . . ) that are connected or assembled together insuch a manner as to give the assembly mechanical cohesion that enablesit to be handled as a single physical entity or object.

These various elements are arranged in an unchanging predeterminedconfiguration which is the configuration they are to have once themodule is integrated in a primary fuselage structure of an aircraft.

According to one possible characteristic, the avionics bay structurepresents a longitudinal dimension and a transverse dimensionperpendicularly to its height, the floor having in cross-section aplurality of floor segments including a central segment and two lateralsegments arranged on either side of the horizontal central segment, eachof the lateral segments being suitable for being hinged relative to thecentral segment in such as a manner as to be capable of adopting firstlya horizontal, deployed position in which all of the segments are inalignment, and secondly a folded position in which each lateral segmentforms an angle other than 180° with the central segment.

This hinged floor makes it easier to install the avionics bay module inthe primary fuselage structure by temporarily reducing the outsidedimensions of the bay module while its lateral floor segments are in thefolded position.

According to other possible characteristics that may be taken inisolation or in combination with one another:

-   -   the floor has a top portion forming a surface for walking on and        a bottom portion that is structural;    -   the structural bottom portion comprises a set of cross-members,        at least some of which that extend in a horizontal transverse        direction are for connecting to the primary fuselage structure;    -   the avionics bay structure incorporates an assembly of avionics        racks receiving electrical and/or electronic equipment;    -   the avionics bay structure comprises two submodules supporting        the floor and arranged on either side of a vertical midplane        including the longitudinal axis of the avionics bay structure;        the floor and the submodules thus form a one-piece mechanical        structure that is easy to manipulate, the two submodules        generally being symmetrical in particular for reasons of        equipment redundancy;    -   the two submodules are separated from each other by a central        passage of longitudinal axis for access to the submodules; the        passage serves in particular to provide a floor surface to        enable installation and/or maintenance personnel to have easy        access to each submodule;    -   each submodule comprises a row of avionics racks receiving        electrical and/or electronic equipment in alignment along the        longitudinal axis of the avionics bay structure, the two rows of        racks being disposed facing each other and spaced apart from        each other;    -   each row of racks comprises a plurality of racks arranged side        by side and spaced apart in pairs by structural vertical        transverse support uprights, the transverse uprights of the two        rows being respectively arranged facing one another; these        uprights serve to support the mechanical load of the racks; each        row of racks thus forms a structural lateral block;    -   the floor is mounted to be supported on each of the vertical        transverse uprights of the two rows of racks; these uprights, in        addition to their function of providing the avionics racks with        mechanical strength, also serve to support the mechanical load        received by the floor and to transmit the forces as received in        this way to the primary structure to which they are fastened in        the lower portion of the bay structure;    -   the floor is fastened to each of the vertical transverse        uprights of the two rows of racks via two support elements that        are transversely spaced apart from each other; this arrangement        serves to reduce the bending force to which the structural        portion (cross-member(s)) of the floor may be subjected, and        thus to adapt its shape accordingly, e.g., by reducing the        height of this structural portion;    -   one of the two support elements is of the flexible support type        and, of the two support elements, constitutes the support        element that is closer to the flexible support element of the        transverse upright facing the opposite row of racks; the        presence of a flexible support serves to reduce the bearing area        of the cross-member in question, and thus to limit bending,        without connecting the racks in statically indeterminate manner        to the cross-members in question;    -   the floor is mounted to be supported on each of the vertical        transverse uprights of the two rows of racks; this arrangement        serves to relieve the floor assembly of forces to which it might        be subjected; and    -   the avionics bay structure incorporates a vertical transverse        partition fastened to the two submodules at one end of the two        opposite longitudinal ends of said structure; this partition        also participates in providing mechanical cohesion to the entire        structure by securing the two submodules together.

The invention also provides an aircraft nose comprising a primaryfuselage structure, the nose being characterized in that it includes anavionics bay module comprising an avionics bay structure incorporatedinside the primary fuselage structure, the avionics bay structure havingan integral floor in its top portion.

The floor carried by the avionics bay structure is already integraltherewith before it is installed as a module in the primary fuselagestructure.

By way of example, the module is installed behind the well for storingthe nose landing gear, in a zone of the fuselage where its cross-sectionis substantially constant.

Nevertheless, such a module may be installed anywhere along thefuselage, and in particular in a zone of cross-section that isquasi-constant.

According to other possible characteristics taken in isolation or incombination with one another:

-   -   the nose comprises, inside the primary fuselage structure, an        aircraft cabin floor that is locally interrupted, the avionics        bay structure being incorporated in the primary fuselage        structure in such a manner that the floor integral with said        avionics bay structure locally extends the aircraft cabin floor;    -   the primary fuselage structure has a plurality of fuselage        frames arranged parallel to one another in cross-sections that        are spaced apart along the longitudinal axis of the nose, the        floor integral with the avionics bay structure including at        least one cross-member in correspondence with a plurality of        frames and, for each of the frames in the plurality of frames,        at least one cross-member that extends in the same transverse        direction as the frame and that connects together two opposite        points of said frame; such an arrangement enables the forces to        which the frames are subjected to be taken up via said at least        one cross-member and the avionics bay structure;    -   the avionics bay structure incorporates a set of avionics racks        for receiving electrical and/or electronic equipment, said at        least one cross-member in correspondence with each frame being        fastened to one or more racks of the set of avionics racks; the        forces taken up by said at least one cross-member are thus        transmitted to the racks of the structure;    -   the set of avionics racks comprises a plurality of vertical        transverse uprights, each lying between two racks arranged side        by side and each extending in the same transverse cross-section        as one of the frames of the plurality of frames, said at least        one cross-member in correspondence with said frame being        fastened to the associated vertical transverse upright; the        forces taken up are thus transmitted in each transverse section        between the frame in question of the fuselage and the structural        support uprights of the racks; and    -   the avionics bay structure presents a longitudinal dimension and        a transverse dimension perpendicularly to its height, the floor        integral with the avionics bay structure having in cross-section        a plurality of floor segments including a central horizontal        segment and two lateral segments arranged on either side of the        central segment, each of the lateral segments being suitable for        being hinged relative to the central segment in such as a manner        as to be capable of adopting firstly a horizontal deployed        position in which all of the segments are in alignment, and        secondly a folded position in which each lateral segment forms        relative to the central segment an angle that is not equal to        180°; in the deployed position, the floor presents a transverse        dimension corresponding substantially to the transverse        dimension between the opposite inside edges of the fuselage        frames to which the lateral floor segments are fastened; this        arrangement in the horizontal deployed position is made possible        because the floor integral with the avionics bay structure is        partially folded (reducing its transverse overall size) during        the operation of installing it in the nose.

The invention also provides a method of integrating an aircraft nose,the nose comprising a primary fuselage structure that defines a spacefor fitting out inside said structure, the space being opened at therear end of the nose, the method being characterized in that itcomprises the following steps:

-   -   inserting an avionics bay module in a longitudinal direction via        the rear end of the nose, the module comprising an avionics bay        structure that has a floor integral with its top portion;    -   moving the avionics bay module inside the primary fuselage        structure towards the front end of the nose until reaching a        location reserved for receiving said avionics bay module; and    -   fastening the module to the primary fuselage structure.

According to other characteristics taken in isolation or in combinationwith one another:

-   -   inside the primary fuselage structure, the aircraft nose        includes an aircraft cabin floor that extends horizontally from        the rear end of the nose towards the front end, the cabin floor        being locally interrupted at a free end of the floor that is        arranged at the rear of the location reserved for the avionics        bay module;    -   the avionics bay module is moved:    -   horizontally over the cabin floor until it reaches a position        situated beyond the free end of the floor and over an opening        situated in register with the space reserved for said module;        and then    -   vertically through said opening in order to reach its location        in which the floor integral with the avionics bay structure        extends the cabin floor forwards;    -   in cross-section, the floor integral with the avionics bay        structure comprises a plurality of floor segments including a        central segment and two lateral segments on either side of said        horizontal central segment, each of the two lateral segments        being hingeable relative to the central segment, the avionics        bay module being inserted inside the nose with the two lateral        segments folded into a position in which each of them forms        relative to the central segment an angle that is not equal to        180°, the module being moved while in this position along a        portion of its path; and    -   during vertical movement of the avionics bay module, the method        includes a step of deploying the lateral floor segments so that        the lateral segments become aligned with the central segment.

It should be observed that the above-described method (in particular thevarious steps and characteristics set out above) applies equally well tointegrating a bay module in an aircraft, in a reserved location that isnot necessarily in the nose of the aircraft. It is possible to installsuch a module anywhere along the fuselage of the aircraft, and inparticular in a zone of cross-section that is quasi constant (e.g.,behind the wing on the lower deck).

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention appear in thefollowing description made by way of non-limiting illustration and withreference to the accompanying drawings, in which:

FIG. 1 (described above) is a general diagrammatic view in longitudinalsection of an aircraft nose of the prior art;

FIGS. 2 and 3 are diagrammatic overall views of an avionics bay modulein an embodiment;

FIG. 4 is a fragmentary perspective view of the inside of the avionicsbay module of FIGS. 2 and 3;

FIG. 5 is a very diagrammatic view in cross-section of the avionics baymodule of FIGS. 2 to 4;

FIG. 6 a is a cross-section view of the avionics bay module of FIGS. 2to 5;

FIG. 6 b is a diagrammatic view in longitudinal section of a flexiblesupport element 102 a, 102 b of FIG. 6 a;

FIG. 7 is a diagrammatic view in longitudinal section of an aircraftnose in an embodiment;

FIG. 8 shows steps of installing an avionics bay module as shown in theview of FIG. 7;

FIGS. 9 a to 9 g show other steps of installing the module incross-section views of the aircraft nose;

FIG. 10 is a diagrammatic cross-section view of a first variantembodiment of the FIG. 6 a module;

FIG. 11 is a diagrammatic cross-section view of a second variantembodiment of the FIG. 6 a module; and

FIG. 12 is a diagrammatic cross-section view of a third variantembodiment of the FIG. 6 a module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown from different viewpoints in FIGS. 2 and 3, an avionics baymodule 50 in an embodiment of the invention is made in the form of anavionics bay structure.

In general, this avionics bay structure comprises a plurality ofelements fastened together so as to form an assembly that is suitablefor being moved as a unit. The elements are connected or assembledtogether so as to confer mechanical cohesion to the assembly enabling itto be handled as a single physical object or entity.

More particularly, the avionics bay structure includes integrated in themodule specifically all of the racks for receiving the various pieces ofelectrical and/or electronic equipment (electrical master boxes,computers, . . . ) dedicated to the avionics bay, and also most of theequipment mounted on those racks (a predetermined number of pieces ofequipment as defined in advance when designing the module), theinterconnections between these pieces of equipment, and also ventilationsystem elements (air ducts, couplings, . . . ), . . . .

The structure of the bay module is thus made up of an assembly ofelements (racks, electrical and/or electronic equipment, elementsproviding interconnections between these pieces of equipment, elementsof ventilation systems, . . . ) that are arranged in a fixedpredetermined configuration that is the configuration they are to haveonce the module has been incorporated in a primary aircraft fuselagestructure.

The structure mainly comprises two submodules 52 (left) and 54 (right)that are arranged symmetrically on either side of a longitudinalvertical midplane P, which is also identified in the OXYZ geometricalreference frame as the plane XOZ.

The axis X is the longitudinal axis of the module 50 and, once installedin an aircraft; it coincides with the longitudinal axis of the fuselageof the aircraft.

The axis Y is transverse and defines the width direction of the module50 (cross-section of the fuselage of the aircraft).

The axis Z is the vertical axis defining the height direction of themodule 50.

The two submodules 52, 54 are separated from each other by a centralpassage 56 aligned along the longitudinal axis X of the module.

In its low portion, the passage 56 has a floor 56 a for walking on togive access to both submodules. This floor extends mainly in the XOYplane and is at a low height up the axis Z.

Each submodule 52, 54 comprises a row of avionics racks aligned alongthe longitudinal axis X. The two mutually parallel rows are thusarranged facing each other on each of two opposite sides of the centralpassage 56.

Each row of racks comprises a plurality of racks, e.g., identical racks,that are arranged side by side.

As shown in FIG. 3 for the right submodule 54 (with the configuration ofthe left submodule 52 being the same), the racks 58, 60, 62, and 64 ofthe row, e.g., four such racks, are separated from one another in pairsby vertical transverse uprights (each situated in the YOZ plane)providing structural support to two adjacent racks (i.e., a mechanicallystrong structural element for the racks). In this example, a row hasfive uprights, with only four of them 59, 61, 63, 65 being shown, sincethe fifth, 57 (visible in FIG. 6 a) is masked by a partition 66 that isdescribed below.

The racks as constituted in this way are said to be “structural” andthey are used for transmitting forces via the transverse uprights.

This makes it possible to avoid having recourse to vertical externalstructural rods for taking up some or all of these forces. Suchstructural rods constitute impediments for moving and/or installingequipment and they increase on-board weight.

The row of racks also includes a common bottom shelf or horizontal base68 to which the transverse uprights 59, 61, 63, 65 of all of the racksin the row are fastened, and shelves that are superposed one aboveanother and fastened between two consecutive transverse uprights.

Thus, for example, the end rack 64 has three superposed shelves 64 a, 64b, and 64 c in addition to the common bottom shelf 68. The top shelf 64c closes the top portion of the rack.

The structure of the other racks 58, 60, and 62 is identical to that ofthe rack 64, and the same applies to the rack of the other row opposite.

Nevertheless, in a variant that is not shown, within a given row, thestructure of the rack may vary from one rack to another or only some ofthem vary. It should be observed that in this variant the verticaluprights of the rack in the two rows face one another in pairs.Furthermore, the shelves of the racks in the two rows are arranged atthe same respective heights.

The symmetry of the structure of the racks from one row to another isnevertheless conserved, e.g., for reasons of equipment redundancybetween the left submodule and the right submodule.

The transverse uprights of a submodule are arranged respectively facingthe corresponding transverse uprights of the other submodule.

The racks constituted in this way are racks having shelves that are usedfor receiving the various pieces of electrical and/or electronicequipment that are needed in the avionics bay.

Such pieces of equipment 70 are shown in the installed position on theshelves of the racks of the left submodule 52 in the background of FIGS.2 and 3. It should be observed that a predetermined number of thesepieces of equipment (and generally most of them) are put into place inthe racks before the module is installed in the aircraft. Certain piecesof equipment (e.g., avionics computers) are nevertheless put into placeonly after the module has been installed.

As mentioned above, the structure of the module 50 incorporates avertical transverse partition 66 (in the YOZ plane) that is fastened toboth of the submodules 52 and 54.

More particularly, this partition 66 is mounted directly on the largetransverse faces of the two vertical transverse uprights 55, 57 situatedat one of the ends 50 a of the two opposite ends 50 a and 50 b of thestructure of the module 50 that are spaced apart from each other alongthe longitudinal axis X. These two uprights 55 and 57 are shown in FIG.6 a.

The partition 66 thus contributes to stiffening the structure by linkingtogether the two submodules, thus making the structure easier to handlewhile it is being installed in the primary aircraft fuselage structure.

The partition 66 is substantially leaktight and it separates the cargohold situated behind it (space 136 in FIGS. 7 and 8) from the avionicsbay module. This partition provides flame resistance in order to reducethe risks of fire in the cargo hold. The partition also has rapiddecompression panels that open in the event of an accident, therebyenabling pressures to be balanced between these two zones.

A central opening 66 a (FIGS. 2 and 3) is formed in the partition inalignment with the central passage 56 so as to enable personnel to enterthe module and also to leave it.

The transverse dimension or width of the central opening 66 a and of thecentral passage 56 is designed to allow a person to pass through.

The height of this central opening may nevertheless be less than theaverage height of a person for reasons of available vertical space.

It should be observed that the rows of racks are spaced apart from eachother as far as possible in order to release efficient empty workingspace in the central passage (in order to enable the equipment 70 to behandled, in particular for maintenance purposes), and also to achieve asmuch safety as possible for systems that are redundant from one row ofracks to the other.

The partition 66 has lateral panels with profiled bottom free ends 66 b,66 c (e.g., chamfered ends) so as to match the shape of the primarystructure of the fuselage of the aircraft within which the module is tobe integrated. This shape is imparted in particular by the (concave)curved shape of the fuselage frames C (FIGS. 4, 5, 6 a).

FIGS. 4 and 5 are diagrams showing the arrangement and the fastening ofthe floor 56 a of the central passage 56 relative to the racks of thesubmodules 52 and 54.

As shown in the fragmentary view in perspective of FIG. 4 and in thediagrammatic cross-section of FIG. 5, the central passage 56 extendsbetween the racks of the left and right submodules 52 and 54.

A seat 71 is provided on the top face of the floor 56 a for use bypersonnel.

The floor is fastened to the racks of the two submodules in the lowportions thereof by means of rigid fasteners 72, 74 (FIG. 5), such asmetal fittings that are spaced apart from one another along the lengthof the passage. More particularly, the fasteners are fastened to thecommon bottom shelf of each row of racks, in register with the verticaltransverse uprights of the racks.

The floor 56 a is held at a distance from the racks by the rigidfasteners and it extends longitudinally between the transverse partition66 common to both submodules and situated at the rear of the module, andthe front end 50 b of the module (FIG. 4).

In FIGS. 4 and 5, the structure of the avionics bay 50 is shown in itsenvironment after being installed in the aircraft.

The front end 50 b of the structure 50 is arranged adjacent to the rearend of a well 76 for storing the nose landing gear (not shown) of theaircraft.

Parallel fuselage frames C of the primary structure of the fuselage ofthe aircraft are also shown in part.

The structure of the avionics bay module 50 also includes in its topportion a floor 80 that constitutes a ceiling and that closes the top ofthe structure, thereby stiffening the two submodules relative to eachother.

The floor 80 is shown in perspective in FIGS. 2 and 3 and incross-section in FIG. 6 a. In FIG. 6 a, the partition 66 is omitted forgreater clarity and a fuselage frame C is shown in dashed lines in orderto illustrate the environment in which the module 50 is installed.

In general manner, the floor 80 comprises a top portion 82 constitutinga surface for walking on made up of a plurality of panels 82 a, 82 b,e.g., made of composite material, and assembled together (FIGS. 2 and3). Underneath it also has a structural portion 84 made up of a set oftransversely extending cross-members for taking up exerted forces viathe fuselage frames. The cross-members are mounted on the racks of thesubmodules in the manner described below.

As shown in general manner in FIG. 2, the floor 80 integral with thestructure comprises a plurality of floor segments, each having a topportion forming a portion of the surface for walking on (panels 82 a, 82b, . . . ) and an underlying bottom portion formed by cross-members andlongitudinal rails.

More particularly, the floor 80 has a stationary horizontal centralsegment 86 and two lateral segments 88 and 90 arranged on either side ofthe central segment (FIGS. 2 and 6 a). In FIG. 6 a, the panels that formthe surface for walking on and that rest on the cross-members areomitted for reasons of clarity.

The two lateral segments 88, 90 are hinge-mounted relative to thestationary central segment 86 so as to enable them to adopt twopositions (FIG. 6 a):

-   -   a horizontal, deployed position, shown in continuous lines in        FIG. 6 a, in which the lateral segments 88, 90 are in alignment        with the central segment (this position is adopted when the        module 50 is installed in the location reserved for it inside        the primary fuselage structure); and    -   a folded position, drawn in dashed lines, in which the lateral        segments 88, 90 are folded towards the lateral flanks of the        racks of the submodules, each forming an angle other than 180°        relative to the central segment 86 (this position is adopted        when the module 50 is in the process of being installed inside        the primary fuselage structure, as described below with        reference to FIGS. 9 a to 9 g).

It should be observed that the central floor segment 86 comprises, underits top portion for constituting the surface for walking on, a set ofcentral cross-members 86 a to 86 e that are parallel to one another anddisposed respectively in register with the vertical transverse uprightsof the racks in the two submodules (FIG. 2).

The stationary central floor segment 86 that overlies the two rows ofracks serves to stiffen the structure, which is useful in particularduring stages in which the module is being handled.

The floor 80 also has two stationary rails or length members 92, 94extending perpendicularly to the central cross-members 86 a to 86 e,above the two respective rows of racks.

Under its top portions dedicated to the surface for walking on, each ofthe lateral floor segments 88, 90 has a respective set of lateralcross-members 88 a to 88 e or 90 a to 90 e, which are arrangedrespectively in the same cross-sections as the central cross-members 86a to 86 e (FIG. 2). The lateral cross-members thus act as top connectingrods for taking up forces laterally.

Each of the lateral cross-members 88 a to 88 e and 90 a to 90 e ishinge-mounted to pivot about a longitudinal axis crossing a respectiveone of the two opposite ends of the central cross-members 86 a to 86 e.Such hinge axes a1 to a2 are shown in FIG. 6 a. The connection betweenthe lateral cross-members and the stationary central cross-member inalignment provides cross-member continuity, thus enabling the twoopposite sides of the fuselage to be connected together in order to takeup forces due to pressurization.

It should be observed that each of the lateral floor segments 88, 90also has a respective rail or length member 96, 98.

The rails 92, 94, 96, and 98 serve to stiffen the structural portion ofthe floor longitudinally, and also to transfer the load of passengerseats that are fastened to the rails in the plane of the floor.

As shown in FIGS. 2, 3, and 6 a, the central floor segment 86 is mountedto be supported on each of said racks of the two submodules, moreparticularly via two spaced-apart support elements arranged in registerwith each of the vertical transverse uprights (FIG. 3).

In FIG. 6 a, the first transverse uprights 55 and 57 of the two rows ofracks are shown together with the two support elements fastened to theirtop portions, the other uprights and support elements being identicaland hidden because they are situated in the background.

The two support elements furthest apart from each other are rigidsupports 100 a, 100 b that are obtained for example by using fastenerfittings (of the clevis-and-lug type) of the same type as the fastenerelements 72 and 74 of the floor 56 a.

Two intermediate support elements 102 a, 102 b of the flexible type ormounted on elastomer are provided to support each central cross-member88 a to 88 e at two additional points.

One such flexible support element 102 a is shown diagrammatically inlongitudinal section in FIG. 6 b.

The support element 102 a (like the support element 102 b) comprises anelastomer block or pad 102 a 1 on which the foot of the centralcross-member 86 a is supported.

The support element 102 a also has a flange 102 a 2 having a horizontalcentral portion from which there extend vertically both a bottom portionand a top portion. The flange is fastened on the rack upright 55 by itsdownwardly extending bottom portion, and its upwardly extending topportion forms a rim extending over the foot of the cross-member 86 awhile leaving vertical clearance relative thereto. The elastomer block102 a 1 is interposed between the horizontal central portion of theflange and the foot of the cross-member 86 a.

The flange mounted with clearance around the flexible support serves tolimit to some extent upward movement of the central cross-member 86 a.

The additional flexible support serves to limit the bending force towhich the central cross-member may be subjected, and thus to reduce theheight of the cross-member without giving rise to horizontal stresses.

When normally loaded, only the spaced-apart support elements 100 a and100 b are stressed and contribute to supporting the integral floor.

In the event of accidental additional loading, the integral floordeforms to a greater extent, so the cross-members also deform to agreater extent and the intermediate flexible support elements 102 a and102 b become loaded and contribute to providing the assembly withmechanical strength. The central cross-member of the floor is thus heldbetter by means of the additional supports 102 a, 102 b. The bearingarea of the cross-member is adapted to the load that is supports. Sincethe cross-member is thus loaded less heavily, it may be made lighter.

It should be observed that the support elements 100 a and 100 b arefastened to the central cross-member 86 a at points that are distinctfrom the respective hinge axes a1 and a2 for hinge-mounting of thelateral cross-members.

This arrangement is easier to make than making a single part (that wouldbe more complicated and more bulky) for uniting on a common axis boththe hinge point of the lateral cross-member and the fastener point ofthe support element 100 a, 100 b.

It is also simpler to dismantle the floor in part when using twodistinct fastener points.

Sloping stiffener elements 101 a and 101 b are provided between therespective pairs of support elements 100 a, 102 a on one side and 100 b,102 b on the other. These additional elements provide the stiffnessneeded along the transverse axis Y in order to prevent deformation ofthe support elements in the event of acceleration along the axis Y.

FIG. 7 is a highly diagrammatic view of an aircraft nose having anavionics bay that is to be integrated therein in one embodiment of theinvention.

As shown diagrammatically in FIG. 7 and given overall reference 120, thenose of the aircraft has a primary fuselage structure 122.

In particular, the primary structure 122 comprises:

-   -   a plurality of mutually parallel fuselage frames C that are        arranged longitudinally along the nose, along the longitudinal        axis X of the nose (the frames being shown in part for clarity);        and    -   a well 76 for storing nose landing gear (not shown) of the        aircraft.

At a front end 120 a, the nose 120 has a housing for a radome zone 126defined by a radome partition 128, and its rear end 120 b is open.

The nose 120 also has a cabin floor 130 that extends from the open rearend 120 b longitudinally towards the front end. The cabin floor 130 isinterrupted over a distance D between a rear floor portion 130 a and afront floor portion 130 b each of which is terminated by a respectivefree end 130 c, 130 d. Between them, the free ends 130 c and 130 ddefine an opening 131.

A cockpit zone 132 is arranged over the front floor portion 130 b.

The rear floor portion 130 a lies in the height direction between theinternal volume or space of the primary structure 122 for fitting out asa rear upper space 134, and a rear lower space 136. Beyond the free endof the floor 130 a, these spaces are united with an overall front freespace 138 for fitting out.

A lower location 140 is reserved in the overall free space 138 inregister with the opening 131 in order to receive an avionics baytherein.

The avionics bay module 50 described above with reference to the figuresand fitted with the assembly of structural elements (racks), withelectrical and/or electronic equipment, with ventilation system elements(ducts, couplings, . . . ), and with interconnection elements (forelectricity, air, . . . ), . . . is to be installed therein inapplication of a method constituting an implementation of the invention.

Prior to inserting the module 50 in the nose 120, the two submodules 52and 54 are assembled together in temporary manner by means of toolingthat mainly comprises support rods.

Such rods are shown very diagrammatically in dashed lines in FIG. 6 a. Asingle rod 142 is shown, the other rods not being visible because theyare arranged in a common alignment.

Each rod is fastened between two facing respective structural supportuprights of the two opposite rows of racks. The rods are in a slopingarrangement so as to subdivide the space of the central passage 56between the rows into two non-deformable triangles as seen in thecross-section view of FIG. 6 a. Such an arrangement thus makes itpossible to prevent the two submodules from moving relative to eachother.

It should be observed that the rods arranged obliquely are notnecessarily provided for each pair of facing structural supportuprights, but that they could be farther apart.

Prior to inserting the module 50 in the nose 120, the lateral floorsegments 88 and 90 are folded into the sloping low position shown indashed lines in FIG. 6 a and they are held temporarily in this closedposition during a portion of the duration of installing the module. Inthis position, the hinge floor of the avionics bay structure presents,in cross-section, a profile that is of trapezoid shape and that issubstantially complementary (and in any event generally close) to theconcave shape of the top portion (ceiling) of the primary fuselagestructure. This position for transporting the module thus matches theinside shape of the fuselage so as to avoid interfering therewith whileit is moving.

It should be observed that the lateral floor segments are held in thisposition, e.g., by means of tooling formed by simple rods connecting thesegments to the uprights of the racks.

FIGS. 8 and 9 a to 9 g show a method of integrating or installing themodule 50 as prepared in this way in the nose 120 until it occupies thelocation 140 reserved therefore.

For this purpose, a traveling crane (not shown in FIG. 8) is put intoplace with its rails arranged inside the primary structure 122 in itsupper portion. The rails are fastened to the fuselage frames C and theyextend up to the location 140.

The avionics module 50 is attached by cables to wheels mounted on therails of the traveling crane and it is inserted into the upper space 134via the open rear end 120 b of the nose.

The module 50 occupying the position 50(A) over the rear cabin floorportion 130 a is then moved in translation towards the front end 120 aas represented by the horizontal arrow (FIG. 8), while being kept spacedapart from the floor and from the top portions of the frames C.

The movement in translation is substantially horizontal (along thelongitudinal axis X) until the intermediate position 50(B) is reachedoverlying the opening 131 (shown in dashed lines in FIG. 8).

The various successive FIGS. 9 a to 9 g, in cross-section view (AA) ofFIG. 8, show a sequence of installing the module 50 from itsintermediate position 50(B) (FIGS. 8 and 9 a) to its final, installedposition (FIGS. 8 and 9 g).

The module 50 is thus lowered vertically through the opening 131 (FIGS.9 a to 9 c). Thereafter, the lateral segments 88, 90 begin to deploylike the wings of a bird (FIG. 9 d). The lateral segments continue torise as the module descends until they reach the fully-deployedhorizontal position (FIG. 9 f) in which the central and lateral floorsegments 86 and 88, 90 are mutually in alignment (open position).

By way of example, the deployment movement may be performed manually.Alternatively, it may be performed by appropriate tooling installedbeside each of the lateral segments or by an actuator system raisingeach lateral segment progressively as the module descends.

In the position of FIG. 9 f, the module is spaced apart from the bottomof the primary fuselage structure so as to make it possible to preparefor docking the module with the various structural elements of theprimary structure.

The downward movement comes to an end in FIG. 9 g when the module hasreached the location 140 reserved therefore (FIG. 8).

It should be observed that in this position (FIG. 9 g), the integralfloor, once deployed, occupies the entire width or transverse dimensionof the fuselage, with this being possible only because the floor can befolded (retracted) in part during the handling stage.

In this installed position, the floor integral with the module 50 andthat acts as a ceiling for the module fits perfectly in the opening 131and thus locally extends the two portions 130 a and 103 b of the cabinfloor.

The cabin floor integral with the module provides an increase in spaceavailable for fitting out inside the module compared with aconfiguration in which the module is positioned under a cabin floor thatis permanently fastened in place.

With such a configuration, it would be necessary to provide verticalclearances between the permanent cabin floor and the module so as toenable the module to be installed under the floor. Such clearances wouldrepresent a loss of volume for integrating equipment in the module. Theracks forming portions of the structure are thus of a height that,depending on requirements, can be greater than that of racks integratedin a module for installation under a permanently fastened floor.

Furthermore, the floor integral with the module enables the module to beput into place via the cabin space (upper space 134 in FIGS. 7 and 8),thus providing a larger passage than would be available if it had topass through the cargo space (lower space 136).

The presence of structural racks (mechanically strong racks) in thestructure of the module makes it possible by using these racks forsupport to make use of cross-members that are relatively short (FIG. 6a) and that can therefore be small in height compared with the height ofthe cross-members of a conventional cabin floor.

This arrangement also makes it possible to further increase the usableheight of the volume within the module.

The module 50 is then fastened to the primary fuselage structure, in itsupper portion via the floor and in its lower portion via the twosubmodules. More particularly, and as shown in FIG. 6 a, each free endof each of the lateral cross-members 88 a to 88 e, 90 a to 90 e of thelateral segments 88, 90 is fastened to a point on a fuselage frame Cthat lies in the same cross-section.

Fastening may be performed for example by means of metal fittings (notshown).

The two fastening points P1 and P2 of a frame are two opposite points inhorizontal alignment.

The module is also fastened to the bottom portion of each frame C viafasteners positioned as close as possible to the frames insofar as thereis no need to leave free space available in this bottom zone. By way ofexample, the fasteners are fittings 150, 152 that are attached at twohorizontally-aligned fastener points P3, P4. The two symmetricalsubmodules are thus held independently of each other to the primaryfuselage structure.

The module 50 is thus fastened in statically indeterminate manner in theYOZ plane to the primary fuselage structure via all of the fuselageframes along which the module extends. The rigid zones of the racks(vertical transverse uprights) thus correspond to rigid zones of thefuselage (the frames) and they are connected thereto via the central andlateral cross-members of the integral floor.

On being installed, the module 50 has the racks for receiving thevarious pieces of equipment (for performing the functions that need tobe performed by a conventional avionics bay) already forming integralportions of the structure of the module so there is no need for them tobe installed subsequently, thereby greatly reducing the integration timein the final assembly line.

The equipment of the module 50 may subsequently have certain pieces ofelectrical and/or electronic equipment added thereto (e.g., avionicscomputers) that are put into place on some of the shelves of the racks.

Pieces of equipment added to the module are connected together and tothe pieces of equipment and the electrical and/or electronic systems(and also the ventilation systems) that were already incorporated in themodule. All of the necessary connections (electricity, air) between thetwo submodules are pre-established before the module is installed,thereby presenting a considerable saving in time on the final assemblyline. Thereafter, the module is connected overall to the electricaland/or electronic systems and to the ventilation provided on the primaryfuselage structure of the aircraft via interface elements that arealready present in the module.

It should be observed that the floor integral with the module alsoserves to convey transverse electrical connections (cables, . . . ) suchas connections 160 shown in FIG. 2, between the two submodules.

Longitudinal electrical connections 162 are also installed in thelateral segments. Likewise, it is possible to provide lower connectionsunder the floor between the two symmetrical submodules.

A first variant of an avionics bay rack 170 is shown verydiagrammatically in FIG. 10.

In this figure, the movable lateral floor segments 172, 174 integratedin the avionics bay module can be folded upwards from the deployedhorizontal position.

They thus occupy an upside-down V-shaped folded position that is capableof being moved without interference inside a primary fuselage structurehaving a cabin height that is greater than that shown in FIGS. 7 and 8.

FIG. 11 shows a second variant embodiment of the FIG. 6 a avionics baystructure.

In this variant that has a module 180 in accordance with the module 50and fastened to the fuselage frames C, the flexible intermediatesupports 102 a and 102 b are omitted. There remain only thefurther-apart supports 100 a and 100 b.

References V1 and V2 designate respective volumes that are needed by thetwo submodules for housing all of the connections for interconnectingthe electrical and/or electronic modules incorporated in each submodule.These volumes are also necessary for connections serving to interconnectthese pieces of equipment and systems with the electrical and/orelectronic systems present in the primary fuselage structure.

FIG. 12 shows a third variant embodiment of a module 190 in which thecentral and lateral cross-members of FIG. 6 a are replaced by a singleone-piece cross-member 192 that extends continuously across the entiretransverse dimension or width of the structure.

Support elements 194, 196 analogous to the support elements 100 a and100 b are positioned in register with the outer edges of the racks foreach one-piece cross-member 192.

Forces exerted on the cross-members of the module floor are taken up bythe structural uprights (which are mechanically strong) of the racks.This makes it possible to reduce the height of the cross-memberscompared with an arrangement in which the cross-members are supported bystructural rods situated on either side of the central racks.

The floor integral with the avionics bay structure and comprising a setof one-piece cross-members of the kind shown in FIG. 12 is not suitablefor being hinged.

As is apparent from the foregoing specification, the invention issusceptible of being embodied with various alterations and modificationswhich may differ particularly from those that have been described in thepreceding specification and description. It should be understood that Iwish to embody within the scope of the patent warranted hereon all suchmodifications as reasonably and properly come within the scope of mycontribution to the art.

1. An avionics bay module, comprising an avionics bay structure with alongitudinal axis for installing in a single operation in a primaryfuselage structure of an aircraft, the avionics bay structure having anintegral floor in a an upper portion of the avionics bay structure. 2.The avionics bay module according to claim 1, wherein the floor forms anintegral portion of the upper portion of the structure of the avionicsbay.
 3. The avionics bay module according to claim 1, wherein theavionics bay structure has the floor integrated with its upper portionprior to being installed in the primary fuselage structure.
 4. Theavionics bay module according to claim 1, wherein the avionics baystructure comprises a plurality of elements fastened to one another soas to form an assembly that is suitable for being moved as a unit. 5.The avionics bay module according to claim 1, wherein the avionics baystructure presents a longitudinal dimension and a transverse dimensionperpendicular to its height, the floor having in cross-section aplurality of floor segments including a central segment and two lateralsegments arranged on either side of the horizontal central segment, eachof the lateral segments being suitable for being hinged relative to thecentral segment in such as a manner as to be capable of adopting firstlya horizontal, deployed position in which all of the segments are inalignment, and secondly a folded position in which each lateral segmentforms an angle other than 180° with the central segment.
 6. The avionicsbay module according to claim 1, wherein the floor has a top portionforming a surface for walking on and a bottom portion that isstructural.
 7. The avionics bay module according to claim 6, wherein thestructural bottom portion comprises a set of cross-members, at leastsome of which that extend in a horizontal transverse direction are forconnecting to the primary fuselage structure.
 8. The avionics bay moduleaccording to claim 1, wherein the avionics bay structure incorporates anassembly of avionics racks receiving at least one of electrical andelectronic equipment.
 9. The avionics bay module according to claim 1,wherein the avionics bay structure comprises two submodules supportingthe floor and arranged on either side of a vertical midplane includingthe longitudinal axis of the avionics bay structure.
 10. The avionicsbay module according to claim 9, wherein the two submodules areseparated from each other by a central passage with a longitudinal axisfor access to the submodules.
 11. The avionics bay module according toclaim 9, wherein each submodule comprises a row of avionics racksreceiving at least one of electrical and electronic equipment inalignment along the longitudinal axis of the avionics bay structure, thetwo rows of racks being disposed facing each other and spaced apart fromeach other.
 12. The avionics bay module according to claim 11, whereineach row of racks comprises a plurality of racks arranged side by sideand spaced apart in pairs by structural vertical transverse supportuprights, the transverse uprights of the two rows being respectivelyarranged facing one another.
 13. The avionics bay module according toclaim 12, wherein the floor is mounted to be supported on each of thevertical transverse uprights of the two rows of racks.
 14. The avionicsbay module according to claim 13, wherein the floor is fastened to eachof the vertical transverse uprights of the two rows of racks via twosupport elements that are transversely spaced apart from each other. 15.The avionics bay module according to claim 14, wherein one of the twosupport elements is of the flexible support type and, of the two supportelements, constitutes the support element that is closer to the flexiblesupport element of the transverse upright facing the opposite row ofracks.
 16. The avionics bay module according to claim 5 wherein thefloor is fastened to each of the vertical transverse uprights of the tworows of racks via two support elements that are transversely spacedapart from each other, and wherein the floor is mounted to be supportedon each of the vertical transverse uprights of the two rows of racks viaits central segment.
 17. The avionics bay module according to claim 9,wherein the avionics bay structure incorporates a vertical transversepartition fastened to the two submodules at one end of the two oppositelongitudinal ends of said structure.
 18. An aircraft nose comprising aprimary fuselage structure, the aircraft nose including an avionics baymodule comprising an avionics bay structure incorporated inside theprimary fuselage structure, the avionics bay structure having anintegral floor in its top portion.
 19. The aircraft nose according toclaim 18, wherein the floor is integral with the top portion of theavionics bay structure.
 20. The aircraft nose according to claim 18,wherein the floor is already integral with the avionics bay structurebefore that structure is installed in the primary fuselage structure.21. The aircraft nose according claim 18, wherein inside the primaryfuselage structure, there is an aircraft cabin floor that is locallyinterrupted, the avionics bay structure being incorporated in theprimary fuselage structure in such a manner that the floor integral withsaid avionics bay structure locally extends the aircraft cabin floor.22. The aircraft nose according to claim 18, wherein the primaryfuselage structure has a plurality of fuselage frame arranged parallelto one another in cross-sections that are spaced apart along thelongitudinal axis of the nose, the floor integral with the avionics baystructure including at least one cross-member in correspondence with aplurality of frames and, for each of the frames in the plurality offrames, at least one cross-member that extends in the same transversedirection as the frame and that connects together two opposite points ofsaid frame.
 23. The aircraft nose according to claim 22, wherein theavionics bay structure incorporates a set of avionics racks forreceiving at least one of electrical and electronic equipment, said atleast one cross-member in correspondence with each frame being fastenedto one or more racks of the set of avionics racks.
 24. The aircraft noseaccording to claim 23, wherein the set of avionics racks comprises aplurality of vertical transverse uprights each lying between two racksarranged side by side and each extending in the same transversecross-section as one of the frames of the plurality of frames, said atleast one cross-member in correspondence with said frame being fastenedto the associated vertical transverse upright.
 25. The aircraft noseaccording to claim 18, wherein the avionics bay structure presents alongitudinal dimension and a transverse dimension perpendicular to itsheight, the floor integral with the avionics bay structure having incross-section a plurality of floor segments including a central segmentand two lateral segments arranged on either side of the central segment,each of the lateral segments being hinged relative to the centralsegment in such as a manner as to be capable of adopting firstly ahorizontal deployed position in which all of the segments are inalignment, and secondly a folded position in which each lateral segmentforms relative to the central segment an angle that is not equal to180°.
 26. The aircraft nose according to claim 22, wherein the avionicsbay structure presents a longitudinal dimension and a transversedimension perpendicular to its height, the floor integral with theavionics bay structure having in cross-section a plurality of floorsegments including a central segment and two lateral segments arrangedon either side of the central segment, each of the lateral segmentsbeing hinged relative to the central segment in such as a manner as tobe capable of adopting firstly a horizontal deployed position in whichall of the segments are in alignment, and secondly a folded position inwhich each lateral segment forms relative to the central segment anangle that is not equal to 180°, and wherein, in the deployed position,the floor presents a transverse dimension corresponding substantially tothe transverse dimension between the opposite inside edges of thefuselage frames to which the lateral floor segments are fastened.
 27. Amethod of integrating an aircraft nose, the nose comprising a primaryfuselage structure that defines a space for fitting out inside saidstructure, the space being opened at the rear end of the nose, themethod comprising the following steps: inserting an avionics bay modulein a longitudinal direction via the rear end of the nose, the modulecomprising an avionics bay structure that has a floor integral with itstop portion; moving the avionics bay module inside the primary fuselagestructure towards the front end of the nose until reaching a locationreserved for receiving said avionics bay module; and fastening themodule to the primary fuselage structure.
 28. The method according toclaim 27, wherein, inside the primary fuselage structure, the aircraftnose includes an aircraft cabin floor that extends horizontally from therear end of the nose towards the front end, the cabin floor beinglocally interrupted at a free end of the floor that is arranged at therear of the location reserved for the avionics bay module.
 29. Themethod according to claim 28, wherein the avionics bay module is moved:horizontally over the cabin floor until it reaches a position situatedbeyond the free end of the floor and over an opening situated inregister with the space reserved for said module; and then verticallythrough said opening in order to reach its location in which the floorintegral with the avionics bay structure extends the cabin floorforwards.
 30. The method according to claim 27, wherein, incross-section, the floor integral with the avionics bay structurecomprises a plurality of floor segments including a central segment andtwo lateral segments on either side of said horizontal central segment,each of the two lateral segments being hingeable relative to the centralsegment, the avionics bay module being inserted inside the nose with thetwo lateral segments folded into a position in which each of them formsrelative to the central segment an angle that is not equal to 180°, themodule being moved while in this position along a portion of its path.31. The method according to claim 29, wherein during vertical movementof the avionics bay module, the method includes a step of deploying thelateral floor segments so that the lateral segments become aligned withthe central segment.